1. Field of the Invention
This invention provides an improved method for the preparation of food, particularly popcorn, in a microwave oven.
2. Description of Related Art
The development of microwave cooking has had an enormous impact on commercial, industrial and home food preparation. The high speed with which cooking occurs, and the broad array of materials suitable for use in microwave ovens have engendered a large number of new uses for microwave ovens. One such use is the preparation of low density snack items, such as by the popping of kernels of corn.
Popping of popcorn in a microwave oven has presented problems, typical of which is the low percentage of popcorn popped. The art is replete with examples of ingenious approaches to reducing the number of "old maids," thereby maximizing the yield of popped corn.
U.S. Pat. No. 3,973,045--Brandberg et al. discloses a corn container made from a compact gusseted paper bag. Unfortunately, this construction still leaves up to 25% of the corn kernels unpopped, and 5% burned after exposure for approximately 21/2 minutes to microwave energy.
A number of solutions involving more efficient use of heat have been proposed to reduce the percentage of corn kernels left unpopped. U.S. Pat. No. 4,038,425--Brandberg et al. discloses a dual-compartmented container. The first compartment is small and contains a charge of popcorn; the second compartment is larger, and provided with pleats, folds or gussets to enable it to expand to hold the popped kernels.
U.S. Pat. No. 4,156,806--Teich et al. and U.S. Pat. No. 4,335,291--Ishino et al. disclose the use of containers for concentrating microwave energy at the base of a conically shaped bowl for the purpose of improving efficiency and speed of popping. One embodiment disclosed by Teich uses a microwave lossy, powdered or particulate material at the base area. The lossy material itself heats up and radiates heat to the kernels located close to it, thereby adding to the heat induced in the kernels. The use of microwave lossy material is a widely known concept in microwave food preparation containers.
U.S. Pat. No. 4,553,010--Bohrer et al. discloses a package for shipping and microwave popping of popcorn having a microwave interactive material integrally attached to the bottom panel of an expandable bag containing popcorn.
In an effort to solve the related problem of excessive heat transfer to the popcorn, U.S. Pat. No. 4,219,573--Borek discloses an expandable popcorn package having an integrated insulating member on the bottom of the package.
The prior art approaches to maximizing the yield of popcorn while minimizing or avoiding burning of the popcorn or the bag, therefore, have relied upon provision of fully integrated containers in which either a thermal insulator or a microwave interactive material is permanently affixed to the bag material. These bags are generally prepared from Kraft paper, and as a result of the inclusion of the microwave interactive material, are both expensive and non-transparent.
U.S. Pat. No. 4,810,844--Anderson discloses a highly efficient microwave popcorn package utilizing a bag having an inwardly pleated bottom panel. The configuration of this bag contrasts favorably to the traditional flat-bottom and side-gusseted bag in which most microwave popcorn is sold at this time. In addition, better popping efficiency is obtained because the popcorn kernels are massed together, rather than spread out. Hence, the greater mass is capable of more efficiently conducting microwave energy. At the same time, by virtue of the unique construction of the bag, the upper opening of the bag through which the edible popcorn ingredients are placed during the packaging process, and through which the popcorn is served after cooking, is quite large, making the packaging and serving processes much more convenient.
A further advantage of the Anderson bag is that it may be prepared from a visible light transparent material. This allows the consumer to watch the corn inside being popped, cutting down on the chances of under- or overcooking the popcorn as well, not to mention the significant entertainment value.
Since the Anderson bag can be made from relatively thin film, the costs of the bag and of the associated final product are, therefore, significantly less than those of current commercial popcorn containers.
However, although the Anderson bag provides the aforementioned advantages, it is still desirable to further increase the yield of the popcorn while maintaining the elegant simplicity of the Anderson bag and serving container.
It is an object of this invention then to provide a method for the popping of corn in a low-cost package with a volume equivalent to that of prior art packages without the necessity for the complex construction of the prior art packages.
It is a further object of this invention to provide an improved method for the preparation of low density food items, or of light loads, in a microwave oven.